DKK1 and neoplasm: We discuss core signaling axes, including osteocyte-derived RANKL/OPG balance, Wnt antagonists (sclerostin/DKK1), mechanotransduction pathways (Piezo1 signaling and connexin-43 hemichannels), and osteocyte paracrine mediators (extracellular vesicles and senescence-associated factors), and examine how each axis modulates tumor cell dormancy, osteolysis, or osteoblastic progression.